Three-dimensional image reconstruction using two light sources

ABSTRACT

Methods and systems for producing a 3D image representation of an in vivo object that include illuminating the object with at least two separate illumination sources included in a wireless imaging device, the first of the at least two illumination sources for illuminating said object from a first side of the object and the second of the at least two illumination sources for illuminating said object from a second side of the object; obtaining at least a first image and a second image of the object, whereby the first image is obtained using a first illumination source, and the second image is obtained using the second illumination source; comparing between photometry measurements of reflected light intensity in the at least first and second images; and constructing a 3D image representation of the object from the at least first and second images, based on said comparison.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of and claims the benefit of andpriority to, U.S. patent application Ser. No. 11/298,265, filed Dec. 9,2005, entitled MEDICAL WIRELESS IMAGING DEVICE, by Doron Adler, et al.,which is a Continuation of U.S. patent application Ser. No. 10/683,344,filed Oct. 14, 2003, now U.S. Pat. No. 7,241,262, granted Jul. 10, 2007,entitled AN IMAGE SENSOR AND AN ENDOSCOPE USING THE SAME by Doron Adler,et al., which is a Divisional of U.S. patent application Ser. No.09/826,163, filed Apr. 5, 2001, now U.S. Pat. No. 6,659,940, grantedDec. 9, 2003, entitled AN IMAGE SENSOR AND AN ENDOSCOPE USING THE SAME,by Doron Adler, et al, which claims the benefit of and priority toIsrael Patent Application Number 135571, filed Apr. 10, 2000. Thecontents of all the foregoing application are hereby incorporated byreference as if recited in full herein.

FIELD OF THE INVENTION

The present invention relates to an image sensor, and more particularlybut not exclusively to two and three-dimensional optical processing fromwithin restricted spaces, and an endoscope using the same.

BACKGROUND

Endoscopy is a surgical technique that involves the use of an endoscope,to see images of the body's internal structures through very smallincisions.

Endoscopic surgery has been used for decades in a number of differentprocedures, including gall bladder removal, tubal ligation, and kneesurgery, and recently in plastic surgery including both cosmetic andre-constructive procedures.

An endoscope may be a rigid or flexible endoscope which consists of fivebasic parts: a tubular probe, a small camera head, a camera controlunit, a bright light source and a cable set which may include a fiberoptic cable. The endoscope is inserted through a small incision; andconnected to a viewing screen which magnifies the transmitted images ofthe body's internal structures.

During surgery, the surgeon is able to view the surgical area bywatching the screen while moving the tube of the endoscope through thesurgical area.

In a typical surgical procedure using an endoscope, only a few smallincisions, each less than one inch long, are needed to insert theendoscope probe and other instruments. For some procedures, such asbreast augmentation, only two incisions may be necessary. For others,such as a forehead lift, three or four short incisions may be needed.The tiny eye of the endoscope camera allows a surgeon to view thesurgical site.

An advantage of the shorter incisions possible when using an endoscopeis reduced damage to the patient's body from the surgery. In particular,the risk of sensory loss from nerve damage is decreased. However, mostcurrent endoscopes provide only flat, two-dimensional images which arenot always sufficient for the requirements of the surgery. The abilityof an endoscope to provide three-dimensional information in its outputwould extend the field of endoscope use within surgery.

The need for a 3D imaging ability within an endoscope has been addressedin the past A number of solutions that provide stereoscopic images byusing two different optical paths are disclosed in U.S. Pat. No.5,944,655, U.S. Pat. No. 5,222,477, U.S. Pat. No. 4,651,201, U.S. Pat.No. 5,191,203, U.S. Pat. No. 5,122,650, U.S. Pat. No. 5,471,237,JP7163517A, U.S. Pat. No. 5,673,147, U.S. Pat. No. 6,139,490, U.S. Pat.No. 5,603,687, WO9960916A2, and JP63244011 A.

Another method, represented by U.S. Pat. No. 5,728,044 and U.S. Pat. No.5,575,754 makes use of an additional sensor that provides locationmeasurements of image points. Patent JP8220448A discloses a stereoscopicadapter for a one-eye endoscope, which uses an optical assembly todivide and deflect the image to two sensors. A further method, disclosedin U.S. Pat. No. 6,009,189 uses image acquisition from differentdirections using one or more cameras. An attempt to obtain 3Dinformation using two light sources was disclosed in U.S. Pat. No.4,714,319 in which two light sources are used to give an illusion of astereoscopic image based upon shadows. JP131622A discloses a method forachieving the illusion of a stereoscopic image by using two lightsources, which are turned on alternately.

An additional problem with current endoscopes is the issue of lightingof the subject for imaging. The interior spaces of the body have to beilluminated in order to be imaged and thus the endoscope generallyincludes an illumination source. Different parts of the field to beilluminated are at different distances from the illumination source andrelative reflection ratios depend strongly on relative distances to theillumination source. The relative distances however may be very large ina typical surgical field of view, distances can easily range between 2and 20 cm giving a distance ratio of 1:10. The corresponding brightnessratio may then be 1:100, causing blinding and making the more distantobject all but invisible.

One reference, JP61018915A, suggests solving the problem of unevenlighting by using a liquid-crystal shutter element to reduce thetransmitted light. Other citations that discuss general regulation ofillumination levels include U.S. Pat. No. 4,967,269, JP4236934A,JP8114755A and JP8024219A.

In general it is desirable to reduce endoscope size and at the same timeto improve image quality. Furthermore, it is desirable to produce adisposable endoscope, thus avoiding any need for sterilization, it beingappreciated that sterilization of a complex electronic item such as anendoscope being awkward in itself.

Efforts to design new head architecture have mainly concentrated onintegration of the sensor, typically a CCD based sensor, with optics atthe distal end. Examples of such integration are disclosed in U.S. Pat.No. 4,604,992, U.S. Pat. No. 4,491,865, U.S. Pat. No. 4,692,608,JP60258515A, U.S. Pat. No. 4,746,203, U.S. Pat. No. 4,720,178, U.S. Pat.No. 5,166,787, U.S. Pat. No. 4,803,562, U.S. Pat. No. 5,594,497 andEP434793B1. Reducing the overall dimensions of the distal end of theendoscope are addressed in U.S. Pat. No. 5,376,960 and U.S. Pat. No.4,819,065, and Japanese Patent Applications No. 7318815A and No. 70221A.Integration of the endoscope with other forms of imaging such asultrasound and Optical Coherence Tomography are disclosed in U.S. Pat.No. 4,869,256, U.S. Pat. No. 6,129,672, U.S. Pat. No. 6,099,475, U.S.Pat. No. 6,039,693, U.S. Pat. No. 5,502,2399, U.S. Pat. No. 6,134,003and U.S. Pat. No. 6,010,449.

Intra-vascular applications are disclosed in certain of theabove-mentioned patents, which integrate the endoscope with anultrasound sensor or other data acquisition devices. Patents thatdisclose methods for enabling visibility within opaque fluids are U.S.Pat. No. 4,576,146, U.S. Pat. No. 4,827,907, U.S. Pat. No. 5,010,875,U.S. Pat. No. 4,934,339, U.S. Pat. No. 6,178,346 and U.S. Pat. No.4,998,972.

Sterilization issues of different devices including endoscopes arediscussed in WO9732534A1, U.S. Pat. No. 5,792,045 and U.S. Pat. No.5,498,230. In particular JP3264043A discloses a sleeve that wasdeveloped in order to overcome the need to sterilize the endoscope.

The above-mentioned solutions are however incomplete and are difficultto integrate into a single endoscope optimized for all the above issues.

SUMMARY

It is an aim of the present embodiments to provide solutions to theabove issues that can be integrated into a single endoscope.

It is an aim of the embodiments to provide an endoscope that is smallerthan current endoscopes but without any corresponding reduction inoptical processing ability.

It is a further aim of the present embodiments to provide a 3D imagingfacility that can be incorporated into a reduced size endoscope.

It is a further aim of the present embodiments to provide objectillumination that is not subject to high contrast problems, for exampleby individual controlling of the light sources.

It is a further aim of the present embodiments to provide a modifiedendoscope that is simple and cost effective to manufacture and maytherefore be treated as a disposable item.

Embodiments of the present invention provide 3D imaging of an objectbased upon photometry measurements of reflected light intensity. Such amethod is relatively efficient and accurate and can be implementedwithin the restricted dimensions of an endoscope.

According to a first aspect of the present invention there is thusprovided a pixilated image sensor for insertion within a restrictedspace, the sensor comprising a plurality of pixels arranged in aselected image distortion pattern, said image distortion pattern beingselected to project an image larger than said restricted space to withinsaid restricted space substantially with retention of an imageresolution level.

Preferably, the image distortion pattern is a splitting of said imageinto two parts and wherein said pixilated image sensor comprises saidpixels arranged in two discontinuous parts.

Preferably, the discontinuous parts are arranged in successive lengths.

Preferably, the restricted space is an interior longitudinal wall of anendoscope and wherein said discontinuous parts are arranged onsuccessive lengths of said interior longitudinal wall.

Preferably, the restricted space is an interior longitudinal wall of anendoscope and wherein said discontinuous parts are arranged onsuccessive lengths of said interior longitudinal wall.

Preferably, the distortion pattern is an astigmatic image distortion.

Preferably, the distortion pattern is a projection of an image into arectangular shape having dimensions predetermined to fit within saidrestricted space.

A preferred embodiment includes one of a group comprising CMOS-basedpixel sensors and CCD based pixel sensors.

A preferred embodiment is controllable to co-operate with alternatingimage illumination sources to produce uniform illuminated images foreach illumination source.

According to a second aspect of the present invention there is providedan endoscope having restricted dimensions and comprising at least oneimage gatherer at least one image distorter and at least one imagesensor shaped to fit within said restricted dimensions, and wherein saidimage distorter is operable to distort an image received from said imagegatherer so that the image is sensible at said shaped image sensorsubstantially with an original image resolution level.

Preferably, the image distorter comprises an image splitter operable tosplit said image into two part images.

Preferably, the image sensor comprises two sensor parts, each separatelyarranged along longitudinal walls of said endoscope.

Preferably, the two parts are arranged in successive lengths alongopposite longitudinal walls of said endoscope.

Preferably, the distorter is an astigmatic image distorter.

Preferably, the astigmatic image distorter is an image rectangulator andsaid image sensor comprises sensing pixels rearranged to complementrectangulation of said image by said image rectangulator.

Preferably, the image distorter comprises at least one lens.

Preferably, the image distorter comprises at least one image-distortingmirror.

Preferably, the image distorter comprises optical fibers to guide imagelight substantially from said lens to said image sensor.

Preferably, the image distorter comprises a second lens.

Preferably, the image distorter comprises at least a secondimage-distorting mirror.

Preferably, the image distorter comprises at least one flat opticalplate.

A preferred embodiment comprises at least one light source forilluminating an object, said light source being controllable to flash atpredetermined times.

A preferred embodiment comprises a second light source, said first andsaid second light sources each separately controllable to flash.

Preferably, the first light source is a white light source and saidsecond light source is an IR source.

In a preferred embodiment, one light source being a right side lightsource for illuminating an object from a first side and the other lightsource being a left side light source for illuminating said object froma second side.

In a preferred embodiment, one light source comprising light of a firstspectral response and the other light source comprising light of asecond spectral response.

A preferred embodiment further comprises color filters associated withsaid light gatherer to separate light from said image into right andleft images to be fed to respective right aid left distance measurers toobtain right and left distance measurements for construction of athree-dimensional image.

In a preferred embodiment, said light sources are configured to flashalternately or simultaneously.

A preferred embodiment further comprises a relative brightness measurerfor obtaining relative brightnesses of points of said object usingrespective right and left illumination sources, thereby to deduce 3dimensional distance information of said object for use in constructionof a 3 dimensional image thereof.

A preferred embodiment further comprises a second image gatherer and asecond image sensor.

Preferably, the first and said second image sensors are arranged back toback longitudinally within said endoscope.

Preferably, the first and said second image sensors are arrangedsuccessively longitudinally along said endoscope.

Preferably, the first and said second image sensors are arranged along alongitudinal wall of said endoscope.

A preferred embodiment comprises a brightness averager operable toidentify brightness differentials due to variations in distances fromsaid endoscope of objects being illuminated, and substantially to cancelsaid brightness differentials.

A preferred embodiment further comprises at least one illuminationsource for illuminating an object with controllable width light pulsesand wherein said brightness averager is operable to cancel saidbrightness differentials by controlling said widths.

A preferred embodiment has at least two controllable illuminationsources, one illumination source for emitting visible light to produce avisible spectrum image and one illumination source for emittinginvisible (i.e. IR or UV) light to produce a corresponding spectralresponse image, said endoscope being controllable to produce desiredratios of visible and invisible images.

According to a third aspect of the present invention there is providedan endoscope system comprising an endoscope and a controller, saidendoscope comprising: at least one image gatherer, at least one imagedistorter and at least one image sensor shaped to fit within restricteddimensions of said endoscope, said image distorter being operable todistort an image received from said image gatherer so that the image issensible at said shaped image sensor with retention of image resolution,said controller comprising a dedicated image processor for processingimage output of said endoscope.

Preferably, the dedicated image processor is a motion video processoroperable to produce motion video from said image output.

Preferably, the dedicated image processor comprises a 3D modeler forgenerating a 3D model from said image output.

Preferably, the said dedicated image processor further comprises a 3Dimager operable to generate a stereoscopic display from said 3D model.

A preferred embodiment comprises an image recorder for recordingimaging.

A preferred embodiment comprises a control and display communicationlink for remote control and remote viewing of said system.

Preferably, the image distorter comprises an image splitter operable tosplit said image into two part images.

Preferably, the image sensor comprises two sensor parts, each separatelyarranged along longitudinal walls of said endoscope.

Preferably, the two parts are arranged in successive lengths alongopposite longitudinal walls of said endoscope.

Preferably, the distorter is an astigmatic image distorter.

Preferably, the astigmatic image distorter is an image rectangulator andsaid image sensor comprises sensing pixels rearranged to complementrectangulation of said image by said image rectangulator.

Preferably, the image distorter comprises at least one lens.

Preferably, the image distorter comprises at least one image-distortingmirror.

Preferably, the image distorter comprises optical fibers to guide imagelight substantially from said lens to said image sensor.

Preferably, the image distorter comprises a second lens.

Preferably, the image distorter comprises at least a secondimage-distorting mirror.

Preferably, the image distorter comprises at least one flat opticalplate.

A preferred embodiment further comprises at least one light source forilluminating an object.

A preferred embodiment comprises a second light source, said first andsaid second light sources each separately controllable to flash.

Preferably, the first light source is a white light source and saidsecond light source is an invisible source.

In a preferred embodiment, one light source is a right side light sourcefor illuminating an object from a first side and the other light sourceis a left side light source for illuminating said object from a secondside.

In a preferred embodiment, one light source comprises light of a firstspectral response and the other light source comprises light of a secondspectral response.

A preferred embodiment comprises color filters associated with saidlight gatherer to separate light from said image into right and leftimages to be fed to respective right and left distance measurers toobtain right and left distance measurements for construction of athree-dimensional image.

Preferably, the light sources are configured to flash alternately orsimultaneously.

A preferred embodiment further comprises a relative brightness measurerfor obtaining relative brightnesses of points of said object usingrespective right and left illumination sources, thereby to deduce 3dimensional distance information of said object for use in constructionof a 3 dimensional image thereof.

A preferred embodiment further comprises a second image gatherer and asecond image sensor.

Preferably, the first and said second image sensors are arranged back toback longitudinally within said endoscope.

Preferably, the first and said second image sensors are arrangedsuccessively longitudinally along said endoscope.

Preferably, the first and said second image sensors are arranged along alongitudinal wall of said endoscope.

A preferred embodiment comprises a brightness averager operable toidentify brightness differentials due to variations in distances fromsaid endoscope of objects being illuminated, and substantially to reducesaid brightness differentials.

According to a fifth embodiment or the present invention there isprovided an endoscope for internally producing an image of a field ofview, said image occupying an area larger than a cross-sectional area ofsaid endoscope, the endoscope comprising an image distorter fordistorting light received from said field of view into a compact shape,and an image sensor arranged in said compact shape to receive saiddistorted light to form an image thereon.

A preferred embodiment comprises longitudinal walls, wherein said imagesensor is arranged along said longitudinal walls, the endoscope furthercomprising a light diverter for diverting said light towards said imagesensor.

Preferably, the image sensor comprises two parts, said distortercomprises an image splitter for splitting said image into two parts, andsaid light diverter is arranged to send light of each image part to arespective part of said image sensor.

Preferably, the sensor parts are aligned on facing lengths of internalsides of said longitudinal walls of said endoscope.

Preferably, the sensor parts are aligned successively longitudinallyalong an internal side of one of said walls of said endoscope.

A preferred embodiment of the image distorter comprises an astigmaticlens shaped to distort a square image into a rectangular shape ofsubstantially equivalent area.

A preferred embodiment further comprises a contrast equalizer forcompensating for high contrasts differences due to differentialdistances of objects in said field of view.

A preferred embodiment comprises two illumination sources forilluminating said field of view.

In a preferred embodiment, the illumination sources are controllable toilluminate alternately, and said image sensor is controllable to gatherimages in synchronization with said illumination sources thereby toobtain independently illuminated images.

In a preferred embodiment, each illumination source is of a differentpredetermined spectral response.

A preferred embodiment of said image sensor comprises pixels, each pixelbeing responsive to one of said predetermined spectral responses.

A preferred embodiment of the image sensor comprises a plurality ofpixels responsive to white light.

In a preferred embodiment, said image sensor comprises a plurality ofpixels responsive to different wavelengths of light.

In a preferred embodiment, the wavelengths used comprise at least threeof red light green light, blue light and infra-red light.

In a preferred embodiment, a second image sensor forms a second imagefrom light obtained from said field of view.

In a preferred embodiment, said second image sensor is placed in back toback relationship with said first image sensor over a longitudinal axisof said endoscope.

In a preferred embodiment, the second image sensor is placed in end toend relationship with said first image sensor along a longitudinal wallof said endoscope.

In a preferred embodiment, the second image sensor is placed across fromsaid first image sensor on facing internal longitudinal walls of saidendoscope.

According to a sixth embodiment of the present invention there isprovided a compact endoscope for producing 3D images of a field of view,comprising a first image sensor for receiving a view of said fieldthrough a first optical path and a second image sensor for receiving aview of said field through a second optical path, and wherein said firstand said second image sensors are placed back to back along alongitudinal axis of said endoscope.

According to a seventh embodiment of the present invention there isprovided a compact endoscope for producing 3D images of a field of view,comprising a first image sensor for receiving a view of said fieldthrough a first optical path and a second image sensor for receiving aview of said field through a second optical path and wherein said firstand said second image sensors are placed end to end along a longitudinalwall of said endoscope.

According to an eighth embodiment of the present invention there isprovided a compact endoscope for producing 3D images of a field of view,comprising two illumination sources for illuminating said field of view,an image sensor for receiving a view of said field illuminated via eachof said illumination sources, and a view differentiator fordifferentiating between each view.

Preferably, the differentiator is a sequential control for providingsequential operation of said illumination sources.

Preferably, the illumination sources are each operable to produceillumination at respectively different spectral responses and saiddifferentiator comprises a series of filters at said image sensor fordifferentially sensing light at said respectively different spectralresponses.

Preferably, the image distorter comprises a plurality of optical fibersfor guiding parts of a received image to said image sensor according tosaid distortion pattern.

According to a ninth embodiment of the present invention there isprovided a method of manufacturing a compact endoscope, comprising:providing an illumination source, providing an image distorter,providing an image ray diverter, providing an image sensor whose shapehas been altered to correspond to a distortion built into said imagedistorter, said distortion being selected to reduce at least onedimension of said image sensor to less than that of an undistortedversion being sensed, assembling said image distorter, said image raydiverter and said image sensor to form an optical path within anendoscope.

According to a tenth embodiment of the present invention there isprovided a method of obtaining an endoscopic image comprising:illuminating a field of view, distorting light reflected from said fieldof view such as to form a distorted image of said field of view havingat least one dimension reduced in comparison to an equivalent dimensionof said undistorted image, and sensing said light within said endoscopeusing at least one image sensor correspondingly distorted.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention and to show how the same maybe carried into effect, reference will now be made, purely by way ofexample, to the accompanying drawings, in which:

FIG. 1 is a simplified block diagram of an endoscope system to whichembodiments of the present invention may be applied,

FIG. 2 is a simplified block diagram of an endoscope system according toa first embodiment of the present invention,

FIG. 3 is a simplified block diagram of a wireless modification of theendoscope of FIG. 2,

FIG. 4 is a simplified schematic block diagram of an endoscope accordingto a preferred embodiment of the present invention,

FIG. 5 is a simplified ray diagram showing optical paths within anendoscope according to a preferred embodiment of the present invention,

FIG. 6 is a ray diagram view from a different angle of the embodiment ofFIG. 5;

FIG. 7 is a ray diagram showing an alternative construction of anoptical assembly according to a preferred embodiment of the presentinvention,

FIG. 8 is a ray diagram showing a further alternative construction of anoptical assembly according to a preferred embodiment of the presentinvention,

FIG. 9 is a ray diagram showing yet a further alternative constructionof the optical assembly according to a preferred embodiment of thepresent invention,

FIG. 10 is a ray diagram taken from the front, of the embodiment of FIG.9,

FIG. 11 is a ray diagram showing yet a further alternative constructionof an optical assembly according to a preferred embodiment of thepresent invention,

FIG. 12 is a simplified layout diagram of an image sensor according toan embodiment of the present invention,

FIG. 13 is a simplified ray diagram showing an endoscope for use in astereoscopic mode according to a preferred embodiment of the presentinvention,

FIG. 14 is a simplified ray diagram showing how a 3D model obtained fromthe embodiment of FIG. 13 can be used to construct a stereoscopic imageof the field of view,

FIG. 15A is a simplified diagram in cross-sectional view showing anarrangement of the image sensors in a stereoscopic endoscope accordingto a preferred embodiment of the present invention,

FIG. 15B is a view from one end of the arrangement of FIG. 15A,

FIG. 16 is a simplified ray diagram showing an alternative arrangementof sensors for obtaining a stereoscopic image of a field of viewaccording to a preferred embodiment of the present invention,

FIG. 17 is a simplified block diagram of a network portable endoscopeand associated hardware usable with preferred embodiments of the presentinvention,

FIG. 18 is a simplified block diagram of an endoscope adapted to performminimal invasive surgery and usable with the preferred embodiments ofthe present invention,

FIG. 19 is a simplified block diagram of an enhanced endoscope systemfor use in research,

FIG. 20 is a simplified block diagram of a configuration of an endoscopesystem for obtaining stereoscopic images, and usable with the preferredembodiments of the present invention, and

FIG. 21 is a simplified block diagram of a system for use inintra-vascular procedures.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present embodiments provide a diagnostic and operative system forminimally invasive diagnosis and surgery procedures, and other medicaland non-medical viewing applications, in particular in which accessconditions dictate the use of small-dimension viewing devices.

Reference is now made to FIG. 1, which is a basic block diagram of abasic configuration of an endoscope according to a first embodiment ofthe present invention. The figure shows a basic configuration of theendoscopic system including interconnections. The configurationcomprises a miniature endoscopic front-end 10, hereinafter simplyreferred to as an endoscope, attached by a wire connection 20 to aprocessing device 30, typically a PC, the PC having appropriate softwarefor carrying out image processing of the output of the endoscope. Theskilled person will appreciate that the wire connection 20 may be anoptical connection or may instead use RF or a like means of wirelesscommunication. The miniature endoscopic front-end 10 may be designed forconnection to any standard PC input (the USB input for example).

The software included with processing device 30 processes the output ofthe miniature endoscopic front-end 10. The software may typicallycontrol transfer of the images to the monitor of the PC 30 and theirdisplay thereon including steps of 3D modeling based on stereoscopicinformation as will be described below, and may control internalfeatures of the endoscopic front end including light intensity, andautomatic gain control (AGC), again as will be described below.

Reference is now made to FIG. 2, which is an internal block diagram ofan endoscope according to a preferred embodiment of the presentinvention. A miniature endoscope 40 is connected by a wire 42 to anadapter 44. The endoscope 40 comprises an image sensor 46 which maytypically comprise a CMOS or CCD or like sensing technology, an opticalassembly 48, a light or illumination source 50, communication interface52 and controller 54. The wired unit of FIG. 2 preferably includes avoltage regulator 56.

As will be explained in more detail below, the image sensor 46 isaligned along the length of a longitudinal side-wall (that is to saysubstantially in parallel with the wall and at least not perpendicularthereto) of the endoscope 40. Such an alignment enables the radialdimension of the endoscope to be reduced beyond the diagonal of theimage sensor 46. Preferably the sensor is arranged in two parts, as willbe explained below.

Reference is now made to FIG. 3, which is an internal block diagram of awireless equivalent of the embodiment of FIG. 2. Parts that areidentical to those shown above are given the same reference numerals andare not referred to again except as necessary for an understanding ofthe present embodiment. In the embodiment of FIG. 3, the wire 42 isreplaced by a wireless link 56 such as an IR or RF link with appropriatesensor, and a battery pack 58.

Reference is now made to FIG. 4, which is an schematic block diagram ofthe miniature endoscope according to a preferred embodiment of thepresent invention. Parts that are identical to those shown above aregiven the same reference numerals and are not referred to again exceptas necessary for an understanding of the present embodiment. Opticalassembly 48 receives light, indicated by arrows 60, from an object beingviewed. The light is processed by optical assembly 48, as will beexplained below, to reach image sensor 46 were it is converted fromphotons into electrical signals. The electrical signals are digitizedand passed to a transmitting device 62, for example an LVDS transmitter,which drives the data through communication link 20 and adapter 44 tothe processing device 30.

Operating power for the endoscope 40 is preferably provided, throughadapter 44, to the voltage regulator 56. Control of the front-end ispreferably carried out by the processor device 30 as discussed above.Control data from the processing device 30 is preferably received at theendoscope 40 by a receiving device 64, which may typically be an LVDSreceiver. Hard wired logic 66 preferably serves as an interface toconvert the incoming control data into signals for controlling both thesensor 46 and the light source 50.

The light source 50 preferably comprises one or more light transmittingdevices such as LEDs, typically a left light source 68 and right lightsource 70. The left and right light sources may be controllable througha driver 72. The functions of each of the above components are describedin greater detail below. As the skilled person will be aware, use ofCMOS and similar technologies for the sensors permit the sensor 46, thetransmitting device 62, the receiving device 64, the hard wired logic66, the driver 72 and the voltage regulator 56 to be integrated into asingle semiconductor Integrated Circuit and such integration isparticularly advantageous in achieving a compact design of endoscope.

Considering the light source 50 in greater detail, it preferablycomprises an integrated array of several white light sources (LEDs forexample) with energy emission in the visible light range mixed,optionally, with IR light sources (LEDs) for purposes that will beexplained below. In fact, any combination of spectral responses may beused, particularly preferred combinations including red+IR andgreen+blue. An integrated array of light sources allows control of eachlight source individually facilitating the following features:

The System is able to turn on the white light source and the IR Lightsource in sequence to generate an IR image every N (user determined)standard white images, for detection by a sensor configuration to bedescribed below with respect to FIG. 12.

The objects being imaged are generally located at a range of differentdistances or field depths from the light source and are consequentlyunevenly illuminated. The more distant areas in the field are dark andare almost invisible while the nearer areas are bright and can becomesaturated. In order to compensate for the uneven illumination intensityover the field, the system preferably exerts control over the intensityof each light source individually, thereby to compensate for reflectedintensity of the objects. An example of an algorithm for control of theillumination array is given as follows:

Given N individual light sources in the illumination array in the camerahead, an initialization process is carried out to generate a referenceimage, preferably a homogeneous white object, to be stored for eachlight source. The stored reference mages (matrices) are identifiedhereinbelow by RIi where i=1, 2 . . . N

Following initialization, imaging is carried out and the input image ofthe field (indicated by matrix II) is divided into M areas such that:M>N. The image areas are identified hereinbelow by Sj j=1, 2, . . . M

Following the above imaging stage, an inner product matrix is calculatedsuch that element Tij of the inner product matrix reflects the innerproduct resulting from taking the II matrix and performing matrixmultiplication with the RIi matrix, in the area Sj and summing theelements of the result metrics.

The resulting inner product matrix is given by T where:

$T = {\overset{M}{\begin{bmatrix}{t\; 11} & {t\; 12} & \ldots & {t\; 1\; M} \\{t\; 21} & \ldots & \ldots & {t\; 2\; M} \\{t\; N\; 1} & \ldots & \ldots & {t\; {NM}}\end{bmatrix}}N}$

and

${Tij} = {{1/{Sj}}{\sum\limits_{P = 1}^{Sj}\; {{{Pij}\left( {{xp},{yp}} \right)} \cdot {{Rj}\left( {{xp},{yp}} \right)}}}}$

wherein

Pij—the intensity of the pixel located in (xp, yp) resulting from lightsource i in area j

Rj—the intensity of the pixel located in (xp, yp) resulting from theinput image in area j

Sj—the total pixels in area j

xp, yp—the pixels coordinates in area j

Next, a vector v is determined that satisfies the following:

Tv-k→Min, where

v—the vector of intensities of each source, and

k—the vector of the desired common intensity, and the solution to thisrequirement is given by

v=(T ^(T) ·T)⁻¹ ·T ^(T) ·k

The central control unit preferably uses the above algorithm topost-process the data to reconstruct a natural look of the image,thereby to compensate for brightness non-uniformities.

In the case of using LEDs as the light source, their fast response timemakes it possible to operate them in a “controllable-flash” mode,replacing the need for variable integration time (or AGC).

Referring now to the image sensor 46, as observed above in respect ofFIG. 2, in the prior art endoscope the size of the sensor provides alimitation on the transverse diameter of the endoscope. Thus, in thepresent embodiment, in order to remove the limitation the sensor isplaced along the longitudinal wall of the endoscope, again preferablysubstantially parallel to the wall but at least not perpendicularthereto. The use of the longitudinal wall not only gives greater freedomto reduce the transverse diameter of the endoscope but also gives thefreedom to increase the length of the sensor, thus increasing imageresolution in the horizontal sense.

As will be explained below, there are two specific embodiments of therealigned sensor, each one associated with a respective design of theoptical assembly as will be described in detail below.

In addition to the above-mentioned geometrical realignment, the sensormay be supplied with color filters to allow acquisition of IR images fordiagnostic purposes or 3D imaging, again as will be described in detailbelow.

Referring now to the geometric design of the sensor, as will beappreciated, the sensor comprises a field of pixels arranged in an arrayover an image-gathering field. The first specific embodiment comprises arearrangement of the pixels in the sensor. Given that for the purposesof example, the sensor width may be divided into say two parts, then thetwo parts may be placed end to end lengthwise. Thus, for example, a512×512 pixels' sensor with pixel dimensions of 10×10 micron, may bedivided into two sections of width 256 pixels each to be placed end toend to give a sensor of 256×1024 pixels and having an overall imagingarea of 2.56 mm×10.24 mm. The longer dimension is preferably placedalong the lengthwise dimension of the endoscope, thus permitting reduceddiameter of the endoscope with no corresponding reduction in theprecision level of the image.

The second specific embodiment likewise relates to a geometricalrearrangement of the pixels. The prior art image sensor has a round orsquare overall sensor or pixilated area, however, if the same number ofpixels are arranged as a rectangle having the same area as the originalsensor but with the height and width freely chosen then the width may beselected to be smaller than the width of the equivalent prior artsensor. More particularly, for an exemplary 512×512 pixels' sensor withpixel dimensions of 10×10 micron the standard prior art sensor (whichwill have a width of 5.12 mm) may be replaced by a rectangular sensorhaving the same overall sensing area as in the previous specificembodiment, but with specific width height dimensions of 2.56 mm×10.24mm, thus becoming easier to fit in the endoscope.

Reference is now made to FIG. 5, which is a ray diagram showing asimplified view from above of optical paths within the endoscope. Aswill be appreciated, in order for the image sensors of the specificembodiments referred to above to produce images which can be recreatedin an undistorted fashion, each sensor is preferably associated with anoptical assembly which is able to redirect image parts in accordancewith the rearrangements of the pixels.

FIG. 5 shows a version of optical assembly 48 designed for the first ofthe two specific embodiments of the image sensor, namely that involvingthe widthwise transfer of pixels. A side view of the same opticalassembly is shown in FIG. 6. FIG. 5 shows a point source object 80, fromwhich light reaches two lenses 82 and 84. The two lenses are selectedand arranged to divide the light into two parts, which parts reach afront-surface-mirror 86. The front surface mirror sends each part of theimage to a different part of the sensor 46, and recovery of the image ispossible by appropriate wiring or addressing of the sensor pixels torecover the original image shape.

Reference is now made to FIG. 7 which is a ray diagram showing analternative version of optical assembly 48, again designed for the firstspecific embodiment of the image sensor. A single lens 86 is positionedin conjunction with two front-surface-mirrors 88 and 90 to deflect lightfrom the object 80 to the mirrors. Each of the two front surface mirrorsrespectively transfers half of the image to the upper or lower part ofthe sensor 46.

Reference is now made to FIG. 8, which is a ray diagram showing a thirdembodiment of the optical assembly 48, this time for the second of thespecific embodiments of the image sensor 46, namely the embodiment inwhich the square shape of pixels is reduced to a rectangular shapehaving smaller width. An asymmetric or astigmatic lens 92 is arranged tofocus light onto a front-surface-mirror 94. The light is distorted bythe lens 92 to undo the distortion introduced into the image by therectangular shape of the sensor 46, and then it is reflected by themirror 94 onto the surface of the sensor 46.

Reference is now made to FIG. 9, which is a ray diagram taken from theside showing a further embodiment of the optical assembly 48. Theembodiment of FIG. 8 necessitates a relatively complicated design of themirror, and in order to obviate such complexity, additional opticaldesign is shown. As shown in FIG. 9, the same astigmatic lens 92 isplaced, not in front of a mirror but rather in front of a series of flatoptical plates 96.1 . . . 96.n, each comprising a diagonal lateral crosssection, the plates each reflecting the light through the respectiveplate to the surface of sensor 46.

Reference is additionally made to FIG. 10, which is a ray diagram, takenfrom the front, of the series of optical plates 96 of FIG. 9. Acomparison between the perspectives of FIG. 9 and FIG. 10 show thelayout of the plates with respect to the endoscope.

Reference is now made to FIG. 11, which is a simplified ray diagramshowing a further embodiment of the optical assembly 48. In theembodiment of FIG. 11, a single lens 98 is preferably used to focuslight from an object 80 to a plane 100 shown in dotted lines. A seriesof optical fibers 102 are lined up over the surface of plane 100 toguide light to desired portions of the surface of the image sensor 46.The fibers 102 are able to direct light as desired and thus can be usedin combination with any arrangement of the sensor pixels that isdesired.

Returning to the construction of the image sensor 46, reference is nowmade to FIG. 12, which is a layout diagram showing a layout of pixels ona sensory surface of an embodiment of the image sensor 46. In FIG. 12,an array comprising pixels of four types is shown, red r, green g, blueb and infra-red IR. The pixels are evenly spaced and allow acquisitionof a colored image when used in conjunction with white light, or an IRimage when used in conjunction with an IR source.

In many cases, important medical information is contained at IRwavelengths. In order to allow acquisition of IR images the sensor ispreferably designed as described above, and using inter alia pixels IRfilters, that is to say color filters that have band passes at IRwavelengths. The sensor is placed in an endoscope in association witheither one or both of a source of visible light and a source ofinfra-red light. Use of the appropriate one of the two light sourcespermits acquisition of either color frames or IR frames as desired. Inone preferred embodiment, IR and color frames are obtainedsimultaneously by operating color and IR light sources together andallowing each pixel to pick up the waveband it has been designed for. Inanother preferred embodiment the color and IR light sources are operatedseparately. Typically one IR frame would be prepared and sent for everyseveral color frames.

Reference is now made to FIG. 13, which is a simplified ray diagramshowing how the endoscope may be used in a stereoscopic mode. Thestereoscopic mode permits the production of 3D images. As with previousfigures the ray diagram indicates rays emanating from a single point,and the skilled person will appreciate how to extrapolate to a fullimage.

In FIG. 13, an endoscope comprises two separate white light sources 110and 112 located at opposite sides of a front opening of the endoscope,respectively being a left light source 110 and a right light source 112.The two white light sources are controlled to light in turn insuccessive short flashes to illuminate an object 114. Light reflected bythe object 114 returns to the endoscope where it strikes a lens 115placed across the front opening and where it is focused on to the planeof sensor 46. The sensor detects the illumination level, which differsbetween the left and right light beams. The ratio of the illuminationlevels may be used to calculate the position of the object and therebyto build up a 3D distance database, as will be explained in greaterdetail below.

As mentioned above, in the stereoscopic mode the left and right lightsources are used sequentially. Comparison between left and rightilluminated images allows a 3D database to be constructed, enablingstereoscopic display of the scene. In the present embodiment, thecomparison between the images is based upon photometry measurements. InFIG. 13, an image 116 of object 114 may be considered as comprising aseries of activated x, y, locations on the detection plane of the sensor46. For each of the x, y locations forming the image 116 on the sensor46, a ratio between the Right Illuminated Image (RII) and the LeftIlluminated Image (LII) may be discerned. The detected ratio may differover the image as it is a function in each case of the distances of therespective light source to the object 114. The left light source 110 andthe right light source 112 have a distance between them which is twiced, d being the length of arrow 117, and the lens has a focal length of1/f, where f is the length of arrow 118. The distance from the lens 115to the plane of the object 114 is denoted by Z and is indicated by arrow120.

The Left Beam Length (LBL) can thus be expressed by:

LBL=√[Z ²+(X−d)²]−√[(Z+1/f)²+(X+x)²]

while the Right Beam Length (RBL) is given by:

RBL=29[Z ²+(X+d)²]−√[(Z+1/f)²+(X+x)²]

where:

X=xZf

Thus the ratio of the light intensity between the left and right lightsources, which is the inverted square of the distance LBL/RBL, may beexpressed as:

LeftToRightRatio=(LBL/RBL)⁽⁻²⁾

The image 116, obtained as described above may now be stored in terms ofa 3D model. The 3D model is preferably displayed as a 3D image byconstructing therefrom two stereoscopic images. The conversion may beperformed using conversion formulae as follows:

yl=yr=−Y/(Z*f)

xl=(−X−D/2)/(Z*f)

xr=(−X+D/2)/(Z*f)

FIG. 13 thus shows how an image of the object can be stored as a 3D database. 3D data of the object is obtained as described above and stored asa database.

Reference is now made to FIG. 14, which is a further simplified raydiagram showing, by means of rays, how the 3D model or database of FIG.13 can be used to obtain a 3D effect at the eyes of an observer. Inorder to display the 3D information using a standard 2D display(monitor) the database is converted into two separate stereoscopicimages, and a display device is used to display each one of thestereoscopic images to a different eye. For example the device may be apair of glasses having a controllable shutter on each on of the eyes.

In FIG. 14, X, Y, 114 and Z 120 represents the three dimensions to beused in the image 119, which corresponds to image 116 as stored in theprevious figure, the object being to reproduce the three dimensionalcharacter of the image by showing different projections of the image toeach of the two eyes of a viewer.

Line 122 represents a projected location on the left image.

Line 124 represents the same projected location as it appears oil theright image.

1/f 118 is the focal length (the amplification factor).

D 126 is the distance between the lenses 128 (representing the eyes).

A preferred embodiment for producing a 3D model using the endoscope usesdifferent color left and right light sources in place of white lightsources. Thus, instead of sequentially illuminating the object fromeither side, it is possible to illuminate the image simultaneously usingboth sources and to use appropriate filters to separate the left andright brightness information. For example a left illumination source 110may be green and right illumination source 112 may be a combination ofred+blue. Such a two-color embodiment is advantageous in that it issimple to control and avoids image distortion problems due to the timelag between acquisitions of the two separate images.

In one alternative embodiment, one of the light sources 110, 112 is avisible light source and the second light source is an IR light source.In the case of an IR light source color filters at the sensor preferablyinclude an IR pass filter. The sensor of FIG. 12, with an arrangement ofIR, red, green and blue detectors as described above may be used.

Reference is now made to FIGS. 15A and 15B which are simplifiedschematic diagrams showing an endoscope according to a preferredembodiment of the present invention for obtaining dual sensorstereoscopic imaging, as will be explained below. FIG. 15A is a sidesectional view and FIG. 15B is a front view.

In the embodiment of FIG. 15A two image sensors 140 and 142 are situatedback to back along a plane of the central axis of an endoscope 144. Eachimage sensor 140 and 142 is associated with a respective opticalassembly comprising a lens 150 and 152 and a mirror 154 and 156. Therespective light source 146, 148, illuminates the entire field of viewas described above and light is gathered by the lens and directed by themirror onto the sensor. The sensors are preferably mounted on a singlePCB 158.

FIG. 15B is a view from the front of the endoscope of FIG. 15A. It willbe noticed that a third optical light source 158 shown. Since thestereoscopic aspect of the image is obtained from the use of two opticalimage paths, as opposed to the previous embodiments which used differentlight sources and different object optical paths, there is now freedomto use any number of light sources as desired to produce desired color(or IR) information.

The back-to-back arrangement of the sensors 140 and 142 along thecentral axis of the endoscope 144 ensures that the endoscope dimensionsare minimized both lengthwise and radially.

Reference is now made to FIG. 16, which is an alternative embodiment ofan endoscope for obtaining dual sensor stereoscopic imaging. Anendoscope 160 comprises two image sensors 162 and 164 arranged in a headto tail arrangement along one longitudinal wall of the endoscope, andagain, as above, preferably parallel to the wall and at least notperpendicular thereto. Illumination sources 166 and 168 are located at afront end 170 of the endoscope and located at the periphery thereof. Twolenses 172 and 174 direct light received from a field of view ontorespective mirrors 176 and 178 each of which is arranged to deflect thelight onto one of the sensors. Each image sensor 162 and 164 thusprovides a slightly different image of the field of view.

It is emphasized that the dual sensor configuration does not decreasethe overall image resolution, because, in accordance with the aboveconfigurations, two full-size image sensors may be used.

The two versions of an endoscope for obtaining dual sensor stereoscopicimaging described above can make use of image sensors either with orwithout color filters. However the sensor of FIG. 12 could be used forone or both of the sensors in either of the embodiments above.

A further preferred embodiment uses a monochrome sensor for one of thetwo image sensors and a color sensor for the second. Such a combinationof one monochrome sensor and one color-filtered sensor in the unitimproves the resolution of the overall image and the sensitivity anddynamic range of the endoscope.

The above embodiments have been described in accordance with the generalendoscope layout given in FIG. 1. In the following, alternativeendoscopic system configurations are described.

Reference is now made to FIG. 17, which is a simplified block diagram ofa network portable endoscope and associated hardware. Parts that areidentical to those shown above are given the same reference numerals andare not referred to again except as necessary for an understanding ofthe present embodiment. An endoscope 10 is connected to a centralcontrol unit 180 where dedicated image processing takes place. Thecontrol unit 180 allows for full motion video to be produced from thesignals emitted by the endoscope. The control unit is connected to alocal display device 182. Additionally or alternatively, a remotecontrol and viewing link 183 may be used to allow remote monitoring andcontrol of the endoscope. The endoscope 10 is preferably a portabledevice and may be powered from a battery pack 184.

Reference is now made to FIG. 18, which is a simplified block diagram ofan endoscope adapted to perform minimal invasive surgery (MIS). Partsthat are identical to those shown above are given the same referencenumerals and are not referred to again except as necessary for anunderstanding of the present embodiment. The most common use ofendoscopic systems is for the performance of MIS procedures by thesurgeon in the operating room. The use of a reduced size endoscopeaccording to the above embodiments enables new procedures to beperformed in which minimal dimensions of the operating equipment isimportant. In FIG. 18, the endoscope 10 is connected to a rack 190. Therack contains accommodation for a full range of equipment that may berequired in the course of use of the endoscope in the operating room,for example a central control unit 180, a high quality monitor 182, aninsufflator 186 etc.

The configuration of FIG. 18, by virtue of the dedicated imageprocessing provided with the control unit 180, gives full motion videowithout requiring fiber-optic and camera head cables.

Reference is now made to FIG. 19, which is a simplified block diagramshowing an enhanced version of the endoscope for use in research. Partsthat are identical to those shown above are given the same referencenumerals and are not referred to again except as necessary for anunderstanding of the present embodiment. The system comprises aminiature endoscopic front-end 10 connected to a highly integrated PCbased central control unit 200 via communication link 20.

The central control unit uses dedicated image processing and thusenables full motion video, displayable locally on display device 182 orremotely via control and display link 183. An optional printer 202 isprovided to print documents and images, including images taken via theendoscope, of the pathologies or stages of the procedure. The systempreferably includes a VCR 204 for recording video produced by theendoscope and a digital storage device 206 allowing archiving of thewhole video. As mentioned above, the system can also be connected viaremote control and viewing link 183, to a remote site for teaching orfor using medical help and guidance. In some hospitals and operatingrooms, in addition to regular operating procedures, research is carriedout. Research procedures generally require additional documentation andcommunication functions. In order to support those requirements a PCbased system with high documentation and communication capabilities isprovided by the enhanced control unit 200. In addition to the externaldevices, an image enhancement software package is used, allowing thegeneration of high quality hard copies of images.

Reference is now made to FIG. 20, which is a simplified block diagramshowing a configuration of endoscope for obtaining stereoscopic (3D)images. Parts that are identical to those shown above are given the samereference numerals and are not referred to again except as necessary foran understanding of the present embodiment. The miniature endoscope 10is connected via a communication link 20 as before to a 3D centralcontrol unit 210, which is the same as the previous control unit 200except that it has the additional capability to construct a 3D modelfrom image information provided by the endoscope. The 3D model can thenbe projected to form a 3D image on a 3D stereoscopic display system 212.The configuration of FIG. 20 may be combined with features taken fromany of the embodiments referred to above.

Recently, new operating procedures requiring stereoscopic (3D) displayhave been developed. In particular such new applications involvedminimally invasive heart and brain procedures. The 3D imagingembodiments referred to above, which may be grouped into multiple lightsource based imaging and dual optical path imaging, can give thenecessary information to construct a 3D model of the scene and togenerate stereoscopic images therefrom.

Reference is now made to FIG. 21, which is a simplified block diagramshowing a variation of an endoscope system for use in intra-vascularprocedures. Parts that are identical to those shown above are given thesame reference numerals and are not referred to again except asnecessary for an understanding of the present embodiment. The systemincludes a long, flexible, thin and preferably disposable catheter 220,a balloon/Stent 222 an endoscope imaging head 224, an X-ray tube 226,X-ray imaging system 228, a video display system 230 and an injectionunit 232.

Intra Vascular procedures are widely used in the medical field. Amongvarious intra-vascular procedures, cardiac catheterization is a verycommon diagnostic test performed thousands of times a day. During theprocedure, catheter 220 is inserted into an artery at the groin or arm.The catheter is directed retrogradely to the heart and to the origin ofthe coronary arteries, which supply blood to the heart muscle. Acontrast substance (“dye”) is injected through the catheter. The use ofan x-ray tube, and an endoscope in conjunction with the dye enables aview of the heart chambers and coronary arteries to be obtained. Theresulting images may be recorded using an x-ray camera and/or theendoscope systems as described above. If an obstruction is detected inone or more of the coronary arteries, the obstruction may be removed andthe artery reopened using techniques such as inserting the balloon andinflating it (PTCA) or inserting a stent, as known to the person skilledin the art.

In intra-vascular operation generally, a few methods may be used toacquire intra-vascular images in the presence of blood. One method isbased on the fact that certain near IR wavelengths allow viewing throughblood. The method thus involves the use of an IR illumination source anda sensor with IR filters as described above. Another method usescontrolled injection of a transparent physiological liquid into theblood vessel in order to dilute the blood prior to the imaging. Yetanother method uses a conical dome, a balloon or any other rigid orflexible and inflatable transparent structure in order to improvevisibility by “pushing” the blood to the walls of the vessels, thusenlarging the part of the optical path that does not include blood.Another way of improving visibility is by using a post-processingalgorithm after the acquiring of the image has been done. Thepost-processing algorithm is based on the extraction of parameters fromthe received image and the use of those parameters in an inverseoperation to improve the image.

There is thus provided an endoscope of reduced dimensions which is ableto provide 2D and 3D images, and which is usable in a range of minimallyinvasive surgical procedures.

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable subcombination.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed hereinabove. Rather the scope of the present invention isdefined by the appended claims and includes both combinations andsubcombinations of the various features described hereinabove as well asvariations and modifications thereof which would occur to personsskilled in the art upon reading the foregoing description.

1. A method of producing a 3D image representation of an in vivo objectcomprising: illuminating the object with at least two separateillumination sources included in a wireless imaging device, the first ofthe at least two illumination sources for illuminating said object froma first side of the object and the second of the at least twoillumination sources for illuminating said object from a second side ofthe object; obtaining at least a first image and a second image of theobject, whereby the first image is obtained using a first illuminationsource, and the second image is obtained using the second illuminationsource; comparing between photometry measurements of reflected lightintensity in the at least first and second images; and constructing a 3Dimage representation of the object from the at least first and secondimages, based on said comparison.
 2. The method of claim 1, comprisingdisplaying the 3D image representation.
 3. The method of claim 1,comprising sequentially illuminating the object with the at least twoseparate illumination sources.
 4. The method of claim 3, wherein theobject is illuminated by white illumination sources.
 5. The method ofclaim 1 wherein illuminating the object comprises illuminatingsimultaneously using the at least two separate illumination sources. 6.The method of claim 5 wherein illuminating the object comprisesilluminating using different color illumination sources.
 7. The methodof claim 6, further comprising using filters to separate different colorinformation.
 8. The method of claim 6 wherein the illumination sourcesinclude a visible illumination source and an invisible illuminationsource.
 9. An imaging system for producing a 3D image representation ofan object in an internal space of a body comprising: a wireless imagingdevice comprising a first image sensor to produce stereoscopic imagedata of the object, said device comprising at least two controllableillumination sources to illuminate the object from a first side of theobject and the from a second side of the object, thereby obtaining atleast two in vivo images through different illumination paths; and aprocessing unit to compare photometry measurements of reflected lightintensity in the at least two in vivo images and to construct a 3D imagerepresentation of the object based on the comparison.
 10. The system ofclaim 9 wherein the first image sensor is for obtaining a first in vivoimage through a first optical path; and wherein the system furthercomprises a second image sensor for obtaining a second in vivo imagethrough a second optical path; whereby the two images providestereoscopic image data.
 11. The system of claim 10 wherein the imagesensors are arranged back to back along a longitudinal axis of saidimaging device.
 12. The system of claim 10 wherein the image sensors arearranged along a longitudinal wall of said imaging device.
 13. Thesystem of claim 9 wherein the illumination sources are operatedsimultaneously.
 14. The system of claim 13 wherein each illuminationsource is controllable to produce illumination of a differentpredetermined spectral response.
 15. The system of claim 13 comprisingcolor filters to separate light from said image into right and leftimages, to obtain right and left distance measurements for theconstruction of the 3D image representation.
 16. The system of claim 14wherein one illumination source emits visible light to produce a visiblespectrum image and one illumination source emits invisible light. 17.The system of claim 9 wherein said image sensor is controllable togather images in synchronization with said illumination sources therebyto obtain independently illuminated images.
 18. The system of claim 9comprising a sequential control for operating said illumination sourcessequentially.
 19. The system of claim 9 wherein the processing unit isexternal to the body.
 20. The system of claim 9 further comprising adisplay to present the 3D image representation.